1. Field of the Invention
The present invention relates to a manufacturing process of a semiconductor electronic device, in particular, a process for compound semiconductor material.
2. Related Prior Arts
Various processes have been known for dividing a processed semiconductor wafer into individual chips by dicing and so on. For instance, the United States Patent, U.S. Pat. No. 6,214,639, has disclosed a process to form grooves and through holes in the scribe region that demarcates individual chips on the wafer so as to leave a limited portion in the scribe as tying bars connecting and supporting chips. Breaking the tying bars, the respective chips may be easily obtained.
Another process to divide the wafer into respective chips has been known in which the process etches along a region in the back surface of the wafer corresponding to the scribe region of the top surface, then the process divides the wafer along the scribe region. In such a process including an etching of the wafer, it is inevitable to fix and support the wafer to be divided. The process ordinarily puts the wafer on a support substrate, such as a glass plate, with resin adhesive.
However, the etching of the wafer sometimes causes a crack in the thinned wafer or the semiconductor layers grown on the wafer. The reason for causing the crack is due to a stress induced therein by an internal force accumulated in the wafer and/or the softened adhesive. The crack extends in random directions, and sometimes reaches a device region formed in the primary surface of the wafer, which directly results in the reduction of the reliability of the device.